Light sensitive element for preparing etching resist for gravure purposes

ABSTRACT

GRAVURE RESIST FILM COMPRISING RESINOUS BINDING LAYERS WHICH PERMIT THE STRIPPING OF THE TEMPORARY SUPPORT FROM THE PHOTOSENSITIVE EMULSION, AFTER WET TRANSFER WITHOUT THE FORMATION OF BLISTERS IN THE EMUSLION. THE INCLUSION OF COMPOUNDS SOLUBLE IN PROCESSING BATHS, SUCH AS HYDROQUINONE, IN A TEMPORARY BINDING VARNISH LAYER, AND ACCORDING TO ANOTHER MODIFICATION, THE INCLUSION OF A WATER SENSITIVE COMPOUND, SUCH AS CASEIN, IN A TEMPORARY BINDING LATEX LAYER, PERMITS THE SIMPLE REMOVAL OF RESINOUS MATERIAL ADHERING TO THE PHOTOSENSITIVE EMULSION, AFTER STRIPPING, WITH 35* TO 40*C. WATER. NO ORGANIC SOLVENT IS REQUIRED FOR THE REMOVAL OF SUCH RESIDUES FROM THE EMULSION.

June 15, 1971 D. J. GALLOIS EI'AL 3,585,037

LIGHT SENSITIVE ELEMENT. FOR PREPARING ETCHING RESIST FOR GRAVUREPURPOSES Filed Feb. 21, 1968 FIG.

HYDROSOL LAYER VARN/5H LAYER \FSUBB/NG LAYER ASUPPORT m u acnmwmmANTI-ABRAS/ON LAYER a f EMuLs/o/v LAYER -A/vr/RALAr/0,v LAYER '-LArExLAYER 4 sues/Na LAYER 3 E SUPPORT 2m PSUBB/NG LAYER i A/vr/cuRL/Na LAYERA 0A N/EL .L GALLO/S CLAUDE L. E GUESTAUX MON/QUE L. LAUVERJAT INVIiN'H)RS BYM A TTOR/VE Y ELEMENT FOR PREPARING ETCHING RESIST FOR GRAVUREPURPOSES Daniel J. Gallois, Claude L. E. Guestaux, and Monique L.

LIGHT SENSITIVE Int. or. time 1/90 US. Cl. 9683 Claims ABSTRACT OF THEDISCLOSURE Gravure resist film comprising resinous binding layers whichpermit the stripping of the temporary support from the photosensitiveemulsion, after wet transfer without the formation of blisters'in'theiemulsion. The inclusion of compounds soluble inprocessingbaths', such as hydroquinone, in a temporary binding 'varnish layer, andaccording to another modification, the inclusion of a water sensitivecompound, such ascasein, in a temporary binding latex 'layer, permitsthe simple removal of resinous material adhering to the photosensitiveemulsion, after stripping, with to C. water. No organic solvent isrequired for the removal of such residues from the emulsion.

This invention relates to light sensitive elements for use in preparingetching resists for gravure purposes. In one embodiment, it concerns theincorporation in resinous binding layers of water soluble compounds.

In Guestaux et al. US. Pat. 3,396,025, issued Aug. 6, 1968, there isdisclosed and claimed a photosensitive product which is useful in thepreparation of a gravure resist and Which comprises a temporary supportof good dimensional stability Which can be easily stripped generallywithout the aid of an organic solvent. The photosensitive productconsists of a customary film support such as of cellulose acetate,polystyrene or polyethylene terephthalate overcoated with layers in thefollowing order: (1) a subbing layer if desired, (2) a water impermeablelayer comprising a polymer of a synthetic resin, this layer being-coatedfrom a solution (varnish) or from a suspension, (3) a stripping layerformed from a hydrosol of an acrylic copolymer as for example a mixtureof gelatin with a copolymer of ethyl acrylate and acrylonitrile, (4) anantihalation layer composed of a gelatin layer containing a dye or CareyLea silver, (5) an unhardened gelatin silver halide emulsion layer andpossibly (6) an antiabrasion layer.

After exposure and tanning development, the'product is applied onto themoist surface of a gravure cylinder. The emulsion layer is placed incontact with the cylinder. The film support is carefully stripped'fr'omthe cylinder permitting the emulsion to adhere to the cylinder followingwhich the emulsion is washed in 35 to 50 C. Water to remove thenontanned areas and to eliminate substances which might remain on theemulsion layer'following' the stripping. I 1 The light sensitive elementdescribed in the aforesaid application yields excellent results andconstitutes an improvement over conventional light sensitive elementswhich elements required cold water to permit stripping of the filmsupport and required special care to prevent the formation of blisterson the emulsion layer. However, many of the synthetic resins employed inthe layers of the light sensitive element-of the aforesaid applicationrequire the use of an organic solvent to facilitate their removal afterwet transfer and stripping of the support from the emulsion layer. Theuse of water, alone, at a temperature of 38 to 50 C. is insufficient forthe re 3,585,037 Patented June 15, 1971 moval of the resinous residuefrom the silver halide emulsion layer in many instances.

Novel light sensitive elements have now been discovered that compriselayers of synthetic resins that may be readily removed from the silverhalide emulsion layer after Wet transfer and stripping of the filmsupport, by simple treatment with water, alone, at a temperature of 35to 40 C. without the necessity for an organic solvent.

In accordance with this invention, a compound, such as hydroquinone,which is soluble in conventional processing baths is incorporated intothe organic solution of the resin which is to constitute the temporarybinding layer or varnish layer of the gravure transfer film. Thismodified varnish results in a resin layer which may be easily removedfrom the silver emulsion layer after wet transfer and stripping, merelyby treatment with water at a temperature of 35 to 40 C.

The photosensitive product of this aspect of the invention thuscomprises, broadly, a gravure resist film comprising a dimensionallystable, temporary, possible subbed film support containing thereon inthe following order: 1) a temporary binding varnish layer composed of anorganic solvent soluble synthetic resin and a compound soluble inprocessing baths, (2) a layer formed from 10 to 15 parts of gelatin andfrom to parts (dry weight) of a lower alkyl acrylate copolymer andcontaining a surface active agent, in which the alkyl acrylate moietiesconstitute from about 60% to about 90% of the Whole weight of thepolymer, hereafter called hydrosol layer (3) an antihalation layer, (4)a light sensitive gelatin silver halide photographic emulsion and ifdesired (5) an antiabrasion layer, all these gelatin containing layersbeing free from hardener agents.

Surprisingly, it has been found that by incorporating a compound that issoluble in the processing baths in the organic solvent solution of thepolymer that is to constitute the temporary binding layer, i.e. thelayer between the subbed support and the hydrosol layer, such polymermay be easily removed from the silver emulsion layer without the needfor an organic solvent. The polymeric residue is easily removed byWashing with 35 to 40 C. water. In addition, the temporary film supportcan be stripped from the emulsion layer without the formation ofstripping blisters in the silver emulsion layer.

According to another aspect of this invention, the temporary bindinglayer may comprise a modified latex layer formed from an aqueousdispersion of a synthetic resin which is insoluble and dispersible inwater and which contains a directly water soluble compound or a watersoluble compound after processing in an alkaline bath, or a waterswellable compound such as casein. Such a compound will be hereaftercalled water sensitive compound. Such a layer will be hereafter calledlatex layer." The inclusion of the water sensitive compound permits theremoval of the latex layer from the photosensitive emulsion, afterstripping of the temporary support, by merely treating with water at atemperature of 35 to 40 C.

The employment of the modified latex layer as a temporary binding layerhas many additional advantages. For example, the modified latex layermay be employed as the sole resinous stripping layer between the supportand the photosensitive emulsion and the hydrosol layer may be dispensed"with, if desired. Also, the modified latex layer is applied from anaqueous suspension of a polymer of a synthetic resin rather than from anorganic solution, as is the case of the temporary binding layerpreviously described. This method of application gives added safety tothe manufacturing operation, since it avoFls the use of solvents thatare volatile and infiam mable.

The film of the modified latex aspect of the invention comprises,broadly, a dimensionally stable, temporary, possibly subbed film supportcontaining thereon in the following order: (1) a temporary binding layerformed from a latex of a synthetic resin which contains a watersensitive compound, (2) an antihalation layer, (3) a light sensitivegelatin silver halide photographic emulsion and if desired (4) anantiabrasion layer, all these gelatin containing layers being free fromhardener agents.

The film support (possibly subbed) of this modification may be easilystripped from the latex coating without the formation of blisters in theemulsion layer, and residues of the modified latex layer may be easilyremoved from the emulsion by contact with water at a temperature of from35 to 40 C.

In the attached illustrative drawing;

FIG. 1 represents a greatly enlarged cross section of a product inaccordance with a preferred embodiment of the invention.

FIG. 2 represents in similar fashion a cross section of a photographicproduct according to a preferred modification of the invention.

FIG. 1 illustrates a product comprising an anticurling layer backing 1and a subbing layer 2 for the support 3 which carries successively andin a superimposed relationship a subbing layer 4 a varnish layer 5, ahydrosol layer 6, an antihalation layer 7, a silver emulsion layer 8 andan antiabarasion layer 9.

FIG. 2 illustrates a photographic product of the modified structure ofthis invention in that the latex layer 10 containing a water sensitivecompound is placed between the subbing layer 4 and the antihalationlayer 7.

The thickness of the layers represented in FIGS. 1 and 2 are notintended to represent the exact scale. For example, the support may havea thickness of about 100 microns, the antihalation layer a thickness ofabout 5 microns, the emulsion layer a thickness of about to microns, theantiabrasion layer and the subbing layers a thickness of about onemicron and the varnish layer 5, synthetic resin layer 6 and latex layer10, a thickness of 2 to 5 microns. It is apparent that some latitudeshould be allowed in the compounding of these various layers to form theproducts described.

As previously mentioned, the modified varnish layer 5 of FIG. 1 isproduced by incorporating compounds which are soluble in the processingbaths, in an organic solution of the polymer which is to constitute thebinding layer. Such compounds include hydroquinone, acrylamide, etc.

Organic solvent soluble synthetic resins which are suitable foremployment in the varnish layer include polyisobutyl methacrylate,polyvinyl butyral, polyvinyl chlorideacetate, polycondensation productsof bisphenol and maleic or fumaric anhydride, polyvinylidene chlorideand acrylonitrile copolymers and the like.

The amount of the soluble compound, e.g. hydroquinone, that is employedin the varnish layer may vary over a wide range. Good results areobtainable with the soluble compounds in amounts of between about 20 andabout 200% by weight of the organic solvent soluble polymer.

The hydrosol layer 6 of FIG. 1 may comprise a mixture of gelatin and asurfactant-containing lower alkyl acrylate copolymer hydrosol such asthat contained in the product of French Pat. No. 1,282,219, thedisclosure of which is hereby incorporated by reference. Thus, thepolymer of the hydrosol may comprise the product resulting from theemulsion polymerization of a mixture of 60 to 90% ethylacrylate and 40to 10% acrylonitrile.

The composition of the hydrosol layer may vary in the ratio of copolymerto gelatin between 90:10 and 85:15, based on solids weight, preferablybeing approximately 87:13. The dry coverage of this layer may be from0.1 to 1.0 gram of solids per square foot with the preferred level at0.3 to 0.4 gram per square foot.

This composition also contains a surfactant present as a result of theemulsion polymerization to prepare the hydrosol. The surface activeagent is an anionic wetting agent having a long hydrophobic chain suchas alkyl or aralkyl, etc. terminating in a sulfate or sulfonate groupand optionally having intermediate polyethoxy, amide or otherhydrophilic groups, such as:

(1) The sodium salt of N-methyl-N-oleyl taurine,

( 2) Tetrasodium-N-(1,2-dicarboxyethyl)-N-octadecyl sulfosuccinamate,

(3) The sodium salt of a p-tertiary-octylphenoxy polyethoxyethyl sulfatewhere the number of ethoxy groups may average 3, but is usually amixture of several chain lengths of different numbers of ethoxy groups,

(4) Sodium lauryl sulfate.

Instead of or in addition to the above, a cationic surface active agentuseful for facilitating stripping is dioctadecyldimethyl-ammoniumchloride, especially of commercial or technical grade.

The working limits of the surface active agent is from 1 to 5% by weightof the dry monomeric material in the preparation of the hydrosols,preferably from 2 to 4%.

The modified latex layer 10 of FIG. 2 is produced by incorporating awater sensitive compound in an aqueous dispersion of a synthetic resinsuch as styrene-butadiene resins, vinylidene chloride-acrylonitrile andethyl acrylateacrylonitrile copolymers; modified polyvinyl chloride, theterpolymers of methyl methacrylate, vinyl chloride and vinyl isobutylether; polyacrylonitrile, styrene polymers plasticized with butylphthalate, and the like.

The inclusion of a water sensitive compound modifies the properties ofthe latex so that the film is readily strippable and the latex layer maybe easily removed from the silver emulsion by treatment with water at atemperature of 35 to 40 C. Such water sensitive compounds includecasein, polymeric materials, such as terpolymers comprising butylacrylate, styrene and methacrylamide, copolymers comprising vinylacetate, or compounds such as hydroquinone, acrylamide, or compoundswhich are water soluble after treatment in alkaline baths, such ascellulose acetate phthalate, etc. Suitable amounts of the watersensitive compounds include from about 2 to about by weight of the solidportion of the latex.

The incorporation of casein into the aqueous polymeric dispersion, whichconstitutes a preferred embodiment, renders the resulting latex layerporous upon wet transfer of the film to the copper cylinder. The latexresidue that remains after stripping may be easily removed from thesilver emulsion layer with water at 35 to 40 C. The principal reason forincorporating the casein into the latex layer is to avoid theundesirable anchoring of the latex layer to the photosensitive emulsionlayer and to the metal parts of the coating apparatus and to permit itseasy removal with warm water. However, the presence of casein in thelatex layer additionally increases the ease of stripping the temporarysupport from the photosensitive emulsion.

The stripping readiness of the casein containing latex coating may befurther enhanced by incorporating therein a polymer which is bothsaponifiable, and compatible with the latex. Such polymeric materialsinclude cellulose acetophthalate, copolymers of vinylmethylether andmaleic anhydride, modified esters of pentaerythrite and colophony,copolymers of styrene and maleic anhydride, and the like. Generally, thesaponifiable polymers may be employed in amounts of from about 2 toabout 50% by weight of the solid portion of the latex.

The support for the photosensitive product may be any film supportcustomarily used which has good dimensional stability, such as celluloseacetate, cellulose acetate bu tyrate, polystyrene, poly(ethylene glycolterephthalate) and the like, wherein the thickness usually runs from0.065 to 0.325 mm. In case of polyester supports even thinner sheets maybe used. Before applying the various layers to a support, it may bedesirable to treat the surface of the support with trichloroacetic acidprior to coating with the various layers which facilitates the adherenceof the layers thereto. The polyester support layer may, if desired, havea subbing layer such as a terpolymer of vinylidene chloride, methylacrylate and itaconic acid, such as disclosed in US. Pat. 3,282,643,cellulose nitrate, etc. This subbing layer overcoated with a thin layerof gelatin is preferred.

The antihalation layer comprises a layer of gelatin con: taining anantihalation dye, such as a yellow Carey Lea silver colloidal dispersionor a manganese dioxide dispersion. The use of a yellow Carey Lea silverdispersion is preferred at the coverage of 0.7 to 0.8 gram per squarefoot, dry weight.

However, some antihalation dyes which may be used in lieu thereof in theantihalation layer include:

(1) Congo red, n

(2) The product which results when 2-naphthylamine- 6,8-disulfonic acidis diazotized and coupled with an equimolar amount of chromotopic acid,

(3) The product (Schultz No. 208) which results when l-naphthylamine-4sulfonic acid is diazotized and coupled with an equimolar amount ofl-naphtholr4-sulfonic acid.

being in unhardened condition is that in use of the eleo ment thegelatin of the silver halide emulsion layer is differentially hardenedin the processing bath so that a tanned image is formed in the emulsionlayer. Hardening of the gelatin in the emulsion layer would interferewith the use of the element in accordance'with the invention.

The antiabrasion layer that may be employed for the protection of thephotosensitive emulsion layer may be of an usual type. A suitableantiabrasion layer is made from a mixture containing, for example, 22parts of starch and 100 parts of gelatin. Such an antiabrasion layer isapplied at a gelatin coverage of 93 mg. per square foot.

An anticurl layer may be utilized as a backing for the photosensitiveelement of this invention, and such layer may be of a compositionsimilar to the antihalation layer described above. This layer preventsthe curling of the support due to the photosensitive emulsion on theopposite side thereof. For example, the anticurl layer may be aconventional gelatin pelloid containing either dyes or manganesedioxide. Other suitable anticurl layers include a nitrocelluloselacquer, an alkyd resin coating or a lacquer including bothnitrocellulose and alkyd resin. These coatings may be applied from asuitable solvent. Other suitable anticurl layers include an unhardenedgelatin layer (thus avoiding the contamination of emulsion layers)containing a compound capable of oxidizing the hardening developer usedin the developing step (for example, pyrogallol), said compound beingsuch as, for example, cupric ferrocyanide, mercuric iodide, lead iodate,methylene blue, etc.

The anticurl layer is preferably of the same thickness as the lightsensitive emulsion layer.

The various layers forming the photosensitive element of this inventionincluding the varnish layer may be applied to the support which has asubbing layer, covered with a thin layer of gelatin, by one of the wellknown techniques such as hopper, scraper, bead coating, transfer byimmersed rollers or any of the other procedures well known in the artfor the application of layers in preparing photographic products. Upondrying of the varnish layer, the hydrosol and antihalation layers arecoated,

6 simultaneously, upon the varnish layer by one of the aforesaidmethods. The silver emulsion layer and the antiabrasion layer areapplied over the antihalation layer in a separate run. The layers areapplied in the order mentioned.- 1 p The same general procedure isemployed in producing the resist film of this invention which includesthe latex layer that contains a water sensitive compound. The latexlayer is applied to a subbed support simultaneously 'with a layer'ofunhardened gelatin which may contain an antihalation dye-Then, in asubsequentrun the silver emulsion and antiabras'ive' layer aresimultaneously coated onto the antihalation layerQThe various layers areapplied in the order mentioned. g

' The film of this invention may he used in any of several gravureprocesses. For example, the element in accordance with the invention maybe subjected to short exposure while in elfective contact with an imageor any other type of element, such as the image modulated light beamfrom a photoelectric scanning devicewhich will impart a latent image tothe silverhalide emulsion, as is well known in the photographic art.

. After exposure, the element, the emulsion of which has been exposed,is developed, fixed, washed and dried, which procedure differentiallyaffects the gelatin of the emulsion layer imparting a hardening andinsolubilizing effect to the gelatin around the silver grains of theimage. A suitable method for processing the film is by a series of stepsas follows: (1) The element is bathed at 68 F. for 2 minutes in adeveloping solution consisting of:

Grams Elon 1.0 Hydroquinone 2.0 Pyrogallic acid 6.0 Sodium sulfite 9.0Potassium bromide 1.5

Sodium sulfate 75.0 Potassium metabisulfite 5.0 Water to make 1 liter.

' (2) The liquid is drained off for 15 seconds.

(3) The element is developed at 68 F. for 2 minutes in an' alkalinesolution consisting of:

Trisodium phosphate grams 100 Sodium sulfate do Phosphoric acid cc 5Water to make 1 liter.

(4) The liquid is drained olf for 15 seconds and rinsed for 60 secondsat 68 F. in a bath consisting of sodium diacetate 10 0 grams, water tomake 1 liter.

(5) Fixing is carried out for 5 minutes at 68 F. in a bath of thefollowing compositions:

Sodium thiosulfate "grams" 240 Sodium sulfite (desiccated) do 10 Sodiumbisulfite do 25 Glacial acetic acid cc 20 Water to make 1 liter.

(6) Wash in running water for 5l0 minutes. (7) Immerse in the followingsolution for 60 seconds at room temperature:

Wetting agent (Kodak Photo-Flo) cc 1O Semicarbazide hydrochloride gram 1Ammonium hydroxide (28%) cc 10 Water to make 1 liter.

or in a solution containing 2 to 4% glycerol inwater,

. (8) Excess liquid is removed and the film is dried at either roomtemperature or elevated temperature (below 30- C.).

After exposure and development, the film is applied to the moist surfaceof a gravure cylinder with the emulsion surface (or the antiabrasionlayer it one is employed) being in contact with the copper cylinder.Following the stripping of the support from the photosensitive layer,the nontanned gelatin along with any resinous material which is aresidue of the resinous binding layers is easily removed by merelytreating with water at 35 to 40 C.

The formation of the etched surface on the copper cylinder may beaccomplished in any conventional manner. For example, the coppercylinder containing the relief image may be etched as follows: some sortof protection such as asphaltum may be applied to the areas of thecopper which are unprotected by the image and are not to be etched. Thecopper may be then subjected to an etching operation such, for example,as with ferric chloride. The copper surface is thereby differentiallyetched inversely to the thickness and hardness of the gelatin whichresides on the surface of the copper. There results relief imagesadapted for use in photogravure printing operations.

The invention will be illustrated by the following examples, but it isto be understood that the invention is not restricted thereto. Thepercentages are by weight unless otherwise specified.

EXAMPLE 1 Thirty grams of a resin comprising polyvinyl acetate chloridemodified by treating with maleic acid are dissolved in a solventcomposed of 940 grams of acetone. To the varnish solution is added gramsof hydroquinone. This solution is then coated onto an Estar [trademarkfor poly(ethylene glycol terephthalate)] support of 0.10 mm. thicknesshaving a subbing layer composed of a terpolymer comprising 83% by weightvinylidene chloride, 15% by weight methylene acrylate and 2% by weightitaconic acid. The coating has a thickness of 2 to 3 microns upondrying. Gelatin is applied over this layer in an amount of 40 mg. persquare decimeter resulting in a gelatin layer having a thickness afterdrying of approximately 5 microns.

Next, there is applied, in succession, a layer of a hydrosol comprisinga dispersion of 453 grams of gelatin in 7200 grams of a latex havingabout 40% solids content and comprising a copolymer of ethyl acrylateand acrylonitrile, an antihalation layer of gelatin containing a CareyLea silver dispersion, a gelatin silver halide emulsion layer and anantiabrasion layer. The dry thickness of the hydrosol coating is 2 to 3microns.

The resulting film is then submitted to the operations of exposure,hardening development and transfer onto a wet copper cylinder. In orderto evaluate the qualities of the resulting material, the stripping forceof a one centimeter wide bit of the unexposed and dry material and ofthe material developed at the time of stripping after 1 wet transferemulsion side onto the copper cylinder are measured with a dynamometerat an angle of 45. The presence or absence of blisters resulting fromstripping on the emulsion is also evaluated by a practical test on alarger sheet of film.

The stripping force of the dry unexposed material and of the materialdeveloped at the time of stripping, i.e. after wet transfer is about 200grams and grams respectively. No formation of blisters is observed afterthe support has been stripped off.

After stripping the support from the element on the cylinder, thenontanned gelatin of the emulsion layer is removed by washing with waterat a temperature of to C. The residues of the varnish and polymer layersare simultaneously removed by this simple water wash treatment. Thegravure cylinder is now ready for etching.

EXAMPLE 2 Forty grams of polyvinyl acetate chloride modified by treatingwith maleic acid are dissolved in a solvent composed of 920 grams ofacetone. In addition, 40 grams of acrylamide are added to the solution.The solution is then coated onto a subbed Estar film base to give acoating having a thickness of 3 to 4 microns upon drying. The hydrosollayer, antihalation layer, gelatin silver 8 halide emulsion layer andantiabrasion layer are applied in succession as in Example 1. Theresultant product is then applied to a copper cylinder in the samemanner as described in Example 1.

The dry stripping forces and those after wet transfer are determined andfound to be about grams and 25 grams respectively. No blisters arenoticeable on the silver emulsion after stripping, The removal of thevarnish and resin layers from the emulsion layer is easily effected byspraying with Water at a temperature of 35 to 40 C.

The following examples illustrate the aspect of this invention in whicha water sensitive compound is incorporated into a latex layer, whichconstitutes the temporary binding layer, so that the varnish layer andthe hydrosol layer may, in some instances, be replaced with a latexlayer.

EXAMPLE 3 Five hundred grams of an anionic aqueous dispersion having apH of 7.5 and composed of a styrene polymer plasticized with butylphthalate and which is comprised of 47% by weight dry material are mixedwith 495 grams of water. The aqueous dispersion is commerciallyavailable under the trade name Vinacryl 4000 from Vinyl Products Ltd.Five grams of casein are added to the latex.

Thereafter, the modified later layer is applied to a subbed Estarsupport and an antihalation layer of gelatin containing Carey Lea silverdispersion, a gelatin silver halide emulsion layer and an antiabrasionlayer are successively coated onto the modified latex layer in themanner of Example 1. The product is then applied to a copper cylinder inthe manner described previously, and the film support is stripped fromthe emulsion layer upon the copper cylinder.

The dry stripping forces and those upon wet transfer are about 50 gramsand about 10 grams respectively. No blisters are formed on the emulsionafter stripping. The modified latex coating is easily removed from theemulsion by merely sprinkling with water at a temperature of 40 C.

EXAMPLE 4 For comparative purposes, the procedure of Example 3 isrepeated, however, the amount of casein employed in the latex layer isincreased to 37.5 grams.

As with the film of the previous example, no blisters are observed onthe emulsion after the temporary support is stripped, and the latexcoating is easily removed by contact with water at a temperature of 40C. Accordingly, it is seen that the percentage of the water sensitivecasein may be varied over a fairly wide range with equally good resultsobtainable.

The following examples illustrate the increased ease of stripping with alatex layer by the incorporation of a polymer that is saponifiable andcompatible with the latex.

EXAMPLE 5 Five hundred grams of Vinacryl 4000 and 7.5 grams of caseinare mixed with 487.5 grams of water. Additionally, 5 grams of celluloseacetophthalate, a saponifiable polymer containing 25% by weightphthaloyl are incorporated into the mixture. The resulting latex layeris coated onto a subbed support and formed into a film as in theprevious examples. The resulting film is exposed and applied to a coppercylinder by wet transfer of the emulsion side onto the cylinder.

The dry adhesive forces and those upon wet transfer are 6 grams in eachcase. No stripping blisters are formed on the emulsion and the latexcoating is very easily removed by means of water at a temperature of 40C.

9 EXAMPLE 6 The procedure of Example is repeated, but the amount ofcellulose acetophthalate is increased to 25 grams.

The dry and Wet stripping forces are identical with those obtained inExample 5. Likewise, no blisters are formed on the emulsion uponstripping. Here again, 40 C. water easily removes the latex coating.

EXAMPLE 7 The procedure of Example 5 is repeated, however, a copolymercomposed of vinylmethylether and maleic anhydride, a modified ester ofpentaerythrite and colophony, and a copolymer of styrene and maleicanhydride which are saponifiable polymers compatible with the latex, aresubstituted for cellulose acetophthalate.

The temporary support of each of the resultant films strips easily, nostripping blisters are formed on the emulsion and the latex is easilyremoved by water at a temperature of 40 C. in each case.

The following examples further illustrate the advantages realized byincorporating a water sensitive polymer into the latex layer.

EXAMPLE 8 Using the same procedure as before, a subbed Estar film baseis coated with an aqueous dispersion comprising 250 grams of a copolymerof styrene and butadiene in a dispersion comprising 47% by weightsolids, 500 grams of a terpolymer composed of butyl acrylate, styreneand methacrylamide as an aqueous dispersion composed of 25% by weightsolids and 250 grams of water. The dry adhesion forces and those uponwet transfer are 150 grams and to 20 grams, respectively. No strippingblisters are formed on the emulsion and the latex coating is easilyremoved by washing with water at a temperature of 40 C.

EXAMPLE 9 The procedure of Example 8 is repeated employing an aqueousdispersion containing 500 grams of Vinacryl 4000, 250 grams of a vinylacetate copolymer, 7.5 grams of casein and 252.5 grams of water.

The dry stripping forces and those upon wet transfer are about 50 gramsand about 10 grams, respectively. As expected, no stripping blisters areformed on the emulsion. The latex layer is easily removed from theemulsion by merely washing with water at a temperature of 40 C.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

We claim:

1. A gravure resist film comprising dimensionally stable, temporary,film support containing thereon -(l) a varnish layer composed of anorganic solvent soluble synthetic resin and about 20 to about 200percent by weight of said resin of a compound soluble in aqueousphotographic processing baths,

(2) a layer composed of 10 to 15 parts of gelatin and to parts (dryWeight) of a surfactant-containing lower alkyl acrylate copolymer latexin which alkyl acrylate units comprise 60 to 90 weight percent of thetotal polymer,

(3) an antihalation layer and (4) a hardener-free light sensitivegelatin silver halide photographic emulsion layer, all in that order.

2. The film of claim 1 wherein the film support is subbed.

3. The film of claim 1 wherein the said emulsion layer has thereon anantiabrasion layer.

4. The film of claim 1 wherein the compound soluble in processing bathsis hydroquinone.

5. The film of claim 1 wherein the compound soluble in processing bathsis acrylamide.

6. The film of claim 1 wherein the varnish layer comprises maleic acidmodified polyvinylacetate chloride and hydroquinone.

7. The film of claim 1 wherein the said acrylate copolymer comprises acopolymer of ethyl acrylate and acrylonitrile.

0. The film of claim 1 wherein said surfactant is an anionic Wettingagent.

9. The film of claim 1 wherein said compound soluble in processing bathsis cellulose acetate phthalate.

10. The film of claim 1 wherein said antihalation layer contains CareyLea silver.

References Cited UNITED STATES PATENTS 3,148,063 9/1964 Yackel et a1.96-83 3,369,903 2/1968 Harvey 96-83 FOREIGN PATENTS 1,282,219 8/1965France 96-83 RONALD H. SMITH, Primary Examiner US. Cl. X.R.

